1. Field of the Invention
This invention relates to an addition-curing type organopolysiloxane composition, and more particularly to an organopolysiloxane composition which has good long-time shelf stability at room temperature.
2. Description of the Prior Art
Heretofore, there are known curable organopolysiloxane compositions which contain an organohydrogenpolysiloxane having a silicon-bonded hydrogen atom (.ident.Si--H) and an organopolysiloxane having a silicon-bonded aliphatic hydrocarbon radical, for example, vinyl radical (.ident.Si--CH.dbd.CH.sub.2) and which utilize the addition of the .ident.Si--H bond to the vinyl radical or the like (i.e., hydrosilylation). Also, there have been proposed organopolysiloxane compositions which are obtained by admixing the curable organopolysiloxane composition of the above-mentioned type with an inhibitor to inhibit the curing reaction at or around room temperature, thereby enhancing the long-time shelf stability, and which can be cured through acceleration of the hydrosilylation by heating at the time of use thereof. For instance, such organopolysiloxane compositions have been proposed which contain, as the inhibitor, an acetylene compound (U.S. Pat. No. 3,445,420), a sulfoxide compound (U.S. Pat. No. 3,453,234) or a hydroperoxide compound (U.S. Pat. No. 4,061,609). However, where an organopolysiloxane composition contains an organohydrogenpolysiloxane having (H)(R').sub.2 SiO.sub.0.5 units wherein the two R' radicals are identical or different univalent hydrocarbon radicals, it is impossible, even by the addition of the above-mentioned inhibitor, to achieve effective inhibition of the curing due to hydrosilylation of the hydrogen atoms in the (H)(R')(--R').sub.2 SiO.sub.0.5 unit and the silicon-bonded aliphatic hydrocarbon radical at a temperature around room temperature. Therefore, such an organopolysiloxane composition has unsatisfactory shelf stability.
It has been proposed to use an amine compound such as n-butylamine, N,N-dibutylaminopropylamine, N,N,N',N'-tetramethylethylenediamine, etc., as an inhibitor for inhibiting the hydrosilylation of a silicon-bonded hydrogen atom located at a terminal of an organohydrogenpolysiloxane and a silicon-bonded aliphatic hydrocarbon radical in an organopolysiloxane at temperatures around room temperature (See U.S. Pat. No. 4,584,361). However, when the amine compound as mentioned above is added to an organopolysiloxane composition containing an organohydrogenpolysiloxane having the (H)(R').sub.2 SiO.sub.0.5 unit, the resultant composition is still unsatisfactory in shelf stability and would show poor curing properties when cured after stored for a long time at room temperature.